Systems for patient support surface orientation and displacement

ABSTRACT

There is provided a backrest pivoting system having a backrest and an actuator for pivoting the backrest. The actuator is pivotably connected to the backrest by a pivot defining a first pivot axis. The backrest is configured to pivot about a guide member which defines a second pivot axis coaxial with the first pivot axis. There is also provided a backrest pivoting system including an actuator and a resilient member mounted in series with the actuator. There is also provided an extendable user support assembly comprising a lower body support panel and a core support panel supported by a frame, the lower body support panel being translatable relative to the frame such that an opening is created between the lower body support panel and the core support panel when the lower body support panel is translated away from the core support panel. There is also provided a method for placing a bed in a vascular position.

CROSS REFERENCE TO RELATED APPLICATIONS

This is a Continuation of U.S. application Ser. No. 14/838,068 filedAug. 27, 2015, which claims priority from U.S. Provisional ApplicationNo. 62/042,438 filed Aug. 27, 2014, which are incorporated herein byreference.

TECHNICAL FIELD

The present invention relates to patient support apparatuses such ashospital beds. In particular, the invention relates to patient supportapparatuses with improved sleep surface characteristics, such as systemsfor orienting the sections of the patient support surface.

BACKGROUND

Patient support apparatuses, such as hospital beds often allow rotationof patient support surfaces in different positions to achieve aplurality of configurations for the bed. Many hospital beds have anelevation system which can raise and lower the frame of the patientsupport surface. Often, these elevation systems are electricallypowered. Examples of configurations for the bed include a lying(sleeping) position, a vascular position with the legs of the patientbeing maintained horizontal and a raised (sitting) position.

Cardiopulmonary resuscitation (CPR) is an emergency procedure performedto restore spontaneous blood circulation and breathing in a person whois in cardiac arrest. It is indicated for those who are unresponsivewith no breathing or abnormal breathing. Cardiac arrest is a medicalemergency that is potentially reversible if treated early. Unexpectedcardiac arrest can lead to death within minutes. A CPR handle istypically provided on hospital beds to speed up the process of loweringthe head section and flattening all sleep surface sections to allowmedical personnel to begin CPR procedures. This is especially useful ifthe head section of the bed is in the fully raised configuration.

The movements of the sections of hospital beds are usually slow so asnot to disturb the patient. Rising and lowering the head sectiontypically take 25 to 35 seconds, and noise and jolts are avoided to theextent possible. In an emergency situation, time is of the essence. Itis therefore acceptable to lower the head section in 5 seconds in thatsituation.

Some actuators available on the market are disengageable. When gears aredisengaged, the time of descent with a heavy patient is less than 2seconds. This is considered too rapid according to medical personnel whofear discomfort or injury for themselves or the patient. Furthermore,safety regulations require that all movement be attended, meaning thatmedical personnel has to hold a handle during the process, letting gowould stop the displacement right away. The actuator is therefore oftenmounted in parallel or in series with a damper. The combined systemslows down the emergency descent to a 5 second duration. A gas springcan further assist the actuator by reducing the effort required by theactuator for rising the head section with a patient present on the bed.

In the event that the CPR handle is released before the head section isfully horizontal and resting on the frame, there is a considerableeffort transmitted to the actuator gears. As a result, the gears can getstripped, the shaft can break and the actuator may need to be replaced.If this occurs, the patient would then need to be transferred to anotherbed.

Some dampers have an integrated spring which can act as a two-step forceto reduce speed when almost compressed. The major drawback of thissolution is that the actuator has to pull its way in to its minimumlength. Most of the actuators have half the force in pull compared topush action. Depending on the strength of the spring, this action maydeteriorate the actuator in the long run.

Medical staff sometimes need to place a patient in the vascular positionto help with blood circulation. The vascular position of the bed frameis obtained by orienting the patient support assembly such that the legsof the patient will be vertically higher or at the same level than thepatient's heart. The foot rest is parallel to the ground in thisposition. This is typically achieved by raising the thigh section firstwhich is usually power activated. The foot end of the bed is thenmanually raised by the medical staff using a pop rod which rises thefoot rest upwards. The thigh section is usually power activated to raiseit to an angle while pushing the thigh rest towards the upper body ofthe patient. The headrest of the bed is typically lowered afterwards toreduce the vertical height of the patient's heart and achieve a fullvascular position.

Because the pop rod is manually operated, the patient can experiencejolts. Furthermore, there is a risk of injury to the medical staffduring the manual operation. Finally, the process has two manual stepswhich tend to take some time. This tends to delay placement of thepatient in the appropriate position. Often, medical personnel do notwant to use a manual system that requires forcing against the patientweight. Furthermore, the system is usually hidden under the sleepsurface foot section and is sometimes unknown to them.

When a patient is taller than average, the bed can be extended toaccommodate his height. There are several ways to extend a bed toaccommodate a taller patient. In some prior art beds, the footboard isremoved and an added accessory is attached at the location freed by theremoval of the footboard. The footboard is sometimes stored but canalternatively be re-attached to the added extension to continue use ofthe controls on the user interface. Some prior art systems lengthen theframe and add a pad to level the extended surface with the mattress top.When the sleep surface is angled or raised in a vascular position, thebolster remains on the frame. In other prior art beds, the extension ispart of the foot section of the bed. It may be manually or powermechanically extended. Usually, the extension is stored above or underthe lower body surface and is pulled away from the upper body surface inuse, the lower body surface and the extension at least partiallyoverlapping in the retracted position. The footboard is typicallyprovided on the extension.

Medical staff sometimes need to pull back the patient towards the headend of the bed after having raised the upper body surface of the bedfrom the flat lying position to a raised seated position. This is causedby the movement of the patient towards the foot of the bed duringrotation. This can cause injuries in medical personnel and discomfortfor the patient.

Example prior art hospital beds are described in US Patent ApplicationPublication Nos. US 20140115785, US 20130145550, US 20130333115, US20140013512, US 20100122415, US 20120005832 and in U.S. Pat. Nos.7,441,291, 6,496,993, 6,968,584, 6,336,235, 5,682,631, 5,906,017,6,640,360, 7,849,539, 8,555,438.

SUMMARY

According to one aspect, there is provided a backrest pivoting systemfor a bed, the bed having a backrest and a frame for supporting thebackrest, the backrest pivoting system comprising: an actuator having afirst actuator end connected to the frame and a second actuator endpivotably connected to the backrest via a pivot defining a first pivotaxis for selectively moving the pivot towards and away from the firstactuator end when the actuator is actuated; at least one guide railsecured to the frame; at least one guide member operatively connected tothe backrest, the at least one guide member engaging the at least oneguide rail for guiding the backrest along a predetermined path duringactuation of the actuator; at least one pivoting link having a first endpivotably connected to the frame and a second end pivotably connected tothe backrest for pivoting the backrest relative to the frame about theat least one guide member during movement of the pivot towards and awayfrom the first actuator end, the at least one guide member defining asecond pivot axis coaxial with the first pivot axis.

In one embodiment, the at least one guide rail is angled relative to theframe to guide the backrest upwardly and away from the first end of theactuator when the backrest is pivoted away from the frame.

In one embodiment, the backrest pivoting system further comprisesspaced-apart first and second lever members and a transversal memberextending between the first and second lever members.

In one embodiment, each lever member comprises a first linear portionand a second linear portion angled relative to the first linear portion.

In one embodiment, the first pivot comprises a pivot bracket dependingfrom the transversal member and a pivot pin extending through the pivotbracket and the second end of the actuator.

In one embodiment, each one of the at least one pivot member comprises aroller member adapted for rotating about the second pivot axis.

In one embodiment, the backrest pivoting system further comprises anorientation sensor operatively connected to the backrest for monitoringthe orientation of the backrest relative to the frame.

In one embodiment, the orientation sensor comprises a potentiometer, afirst sensor arm pivotably connected to one of the at least one guidearm and a second sensor arm pivotably connected to the first sensor armand to the potentiometer.

In one embodiment, the backrest pivoting system further comprises aresilient member connected in series with the actuator between the frameand the actuator.

According to another aspect, there is also provided a backrest pivotingsystem for a bed, the bed having a frame and a backrest pivotablyconnected to the frame, the backrest pivoting system comprising: anactuator having a first actuator portion connected to the frame and asecond actuator portion connected to the backrest for pivoting thebackrest relative to the frame, the actuator further having atransmission adapted for operatively coupling the second actuatorportion to the first actuator portion; a release operatively connectedto the transmission, the release being movable between a locked positionin which the first actuator portion is coupled to the second actuatorportion and an unlocked position in which the second actuator portion isdecoupled from the first actuator portion to allow free pivoting of thebackrest towards the frame; a resilient member connected in series withthe actuator between the frame and the actuator, the resilient memberbeing compressible when the release is moved from the unlocked positioninto the locked position as the backrest pivots towards the frame.

In one embodiment, the backrest pivoting system further comprises adamper connected in parallel to the actuator, the damper beingconfigured to provide damping during the pivoting of the backresttowards the frame.

In one embodiment, the actuator is a linear actuator.

In one embodiment, the resilient member comprises a helical spring.

In one embodiment, the backrest pivoting system further comprises ahousing secured to the frame for housing the resilient member.

In one embodiment, the first actuator portion is pivotably connected tothe housing.

In one embodiment, the backrest pivoting system further comprises anactuator pivot pin extending transversely through the housing and thefirst actuator portion, the housing comprising at least one opening forreceiving the actuator pivot pin.

In one embodiment, the at least one opening is elongated to allow theactuator pivot pin to move relative to the housing when the resilientmember is compressed.

According to yet another aspect, there is also provided an extendablesupport assembly for a bed comprising: a frame; a core support panelsupported by the frame; a lower body support panel supported by theframe, the lower body surface being located adjacent the core supportpanel, the lower body support panel being translatable along the frameaway from the core support panel to form an opening between the lowerbody support panel and the core support panel.

In one embodiment, the extendable support assembly further comprises anextension member having a first end pivotably connected to the coresupport panel and a second end telescopically engaging the lower bodysupport panel.

According to yet another aspect, there is also provided a support panelpivoting system for a bed, the bed having a frame, a backrest pivotablyconnected to the frame and a lower body support panel pivotablyconnected to the frame, the support panel pivoting system comprising: abackrest actuator having a first actuator portion connected to the frameand a second actuator portion connected to the backrest for pivoting thebackrest relative to the frame, the backrest actuator further having atransmission adapted for operatively coupling the second actuatorportion to the first actuator portion; a release operatively connectedto said transmission, the release being movable between a lockedposition in which the first actuator portion is coupled to the secondactuator portion and an unlocked position in which the second actuatorportion is decoupled from the first actuator portion to allow freepivoting of the backrest towards the frame; a sensor for determiningthat the release is in the unlocked position; a lower body actuatoroperatively connecting the lower body support panel to the frame forpivoting the lower body support panel relative to the frame, the lowerbody actuator being further operatively connected to the sensor forpivoting the backrest towards the frame when the release is in theunlocked position and that the backrest is pivoted downwardly.

In one embodiment, the sensor is operatively connected to the backrest.

In one embodiment, the sensor comprises an orientation sensor fordetermining an orientation of the backrest.

In one embodiment, the system comprises a control unit operativelyconnected to the orientation sensor for determining a pivoting speed ofthe backrest based on the orientation of the backrest.

In one embodiment, the control unit is further configured fordetermining that the release is in the unlocked position when thepivoting speed of the backrest is above a threshold speed value.

In one embodiment, the threshold speed value is 8 degrees per second.

In one embodiment, the control unit is further configured fordetermining that the backrest is being pivoted downwardly towards theframe.

In one embodiment, the control unit is further operatively connected tothe lower body actuator for actuating the lower body actuator upon adetermination that the pivoting speed of the backrest is above thethreshold speed value and that the backrest is being pivoted towards theframe.

According to yet another aspect, there is also provided a method forplacing a bed in a vascular position, the bed having a patient supportassembly mounted onto a frame having a head end and a foot end, thepatient support assembly including a backrest located near the head end,a lower body surface located near the foot end and a core body surfacelocated between the backrest and the lower body surface, the core bodysurface being pivotably interconnected to the lower body surface, themethod comprising: receiving a command to place the bed in the vascularposition; pivoting the core support panel at a thigh angle above theframe; pivoting the lower body support panel at a lower body angle abovethe frame; pivoting the backrest at a back angle above the frame;tilting the frame at a tilt angle relative to the horizontal such thatthe head end of the frame is located below the horizontal, said pivotangle being within a predetermined range of said foot angle, therebyplacing the bed in the vascular position.

In one embodiment, pivoting the core support panel comprises raising arear end of the core support panel located towards the lower bodysupport panel.

In one embodiment, raising the rear end of the core support panelfurther comprises raising a front end of the lower body panel locatedtowards the core support panel, the rear end of the core support panelbeing hingeably connected to the front end of the lower body panel via ahinge connection.

In one embodiment, raising the rear end of the core support panel andraising the front end of the lower body panel comprising actuating alower body actuator having a first end pivotably connected to the frameand a second end pivotably connected to the hinge connection.

In one embodiment, the tilting of the frame is performed after theraising of the core body support panel and the raising of the backrest.

In one embodiment, the raising of the core body support panel, theraising of the backrest and the tilting of the frame are performedsimultaneously.

In one embodiment, the core angle is 30 degrees, the lower body angle is13 degrees, the back angle is 13 degrees and the tilt angle is 13degrees.

BRIEF DESCRIPTION OF THE DRAWINGS

Having thus generally described the nature of the invention, referencewill now be made to the accompanying drawings, showing by way ofillustration example embodiments thereof and in which:

FIG. 1 is a top perspective view of a hospital bed, in accordance withone embodiment;

FIG. 2 is an isolated, top perspective view of a patient supportassembly for the hospital bed illustrated in FIG. 1;

FIG. 3 is a top plan view of the patient support assembly illustrated inFIG. 2;

FIG. 4 is a bottom plan view of the patient support assembly illustratedin FIG. 2;

FIG. 4A is a partial bottom perspective view of the patient supportassembly illustrated in FIG. 2, taken from area A-A of FIG. 4, enlargedto show details of the left CPR handle assembly;

FIG. 5 is a partial bottom perspective view of the patient supportassembly illustrated in FIG. 2, enlarged to show details of the backrestpivoting system;

FIG. 5A is a partial bottom plan view of the patient support assemblyillustrated in FIG. 2, enlarged to show details of the backrest pivotingsystem;

FIG. 5B is a perspective view of the right lever member, the right guiderail and the right guide member of the backrest pivoting systemillustrated in FIG. 2, shown in isolation to better appreciate theconfiguration of these elements;

FIG. 6 is a side elevation view of the patient support assemblyillustrated in FIG. 2, with the backrest abutting the frame;

FIG. 6A is an enlarged cross-sectional view of the patient supportassembly illustrated in FIG. 6, taken along cross-section line X-X ofFIG. 3;

FIG. 6B is a schematic drawing of the patient support assemblyillustrated in FIG. 6, with only the backrest and the right framemember, guide rail, guide member, lever member and pivoting link shownand all other parts removed for clarity;

FIG. 7 is a side elevation view of the patient support assembly similarto that illustrated in FIG. 2, with the backrest pivoted upward at a20-degree angle relative to the frame;

FIG. 7A is an enlarged cross-sectional view of the patient supportassembly similar to that illustrated in FIG. 6A, with the backrestpivoted upward at a 20-degree angle relative to the frame;

FIG. 7B is a schematic drawing of the patient support assembly similarto that illustrated in FIG. 6B, with the backrest pivoted upward at a20-degree angle relative to the frame;

FIG. 8 is a side elevation view of the patient support assemblyillustrated in FIG. 2, with the backrest pivoted upward at a 40-degreeangle relative to the frame;

FIG. 8A is an enlarged cross-sectional view of the patient supportassembly similar to that illustrated in FIG. 6A, with the backrestpivoted upward at a 40-degree angle relative to the frame;

FIG. 8B is a schematic drawing of the patient support assembly similarto that illustrated in FIG. 6B, with the backrest pivoted upward at a40-degree angle relative to the frame;

FIG. 9 is a side elevation view of the patient support assemblyillustrated in FIG. 2, with the backrest pivoted upward at a 60-degreeangle relative to the frame;

FIG. 9A is an enlarged cross-sectional view of the patient supportassembly similar to that illustrated in FIG. 6A, with the backrestpivoted upward at a 60-degree angle relative to the frame;

FIG. 9B is a schematic drawing of the patient support assembly similarto that illustrated in FIG. 6B, with the backrest pivoted upward at a60-degree angle relative to the frame;

FIG. 10 is a side elevation view of the hospital bed illustrated in FIG.1, with the barrier system removed and with the frame tilted and thebackrest, the lower support panel and the core support panel orientedsuch that the bed is in a vascular configuration;

FIG. 10A is a cross-sectional view of the hospital bed illustrated inFIG. 1, taken along a longitudinal axis of the bed, with the barriersystem removed and with the frame tilted and the backrest, the lowerbody support panel and the core support panel oriented such that the bedis in a vascular configuration;

FIG. 10B is a partial, top rear perspective view of the hospital bedillustrated in FIG. 10, with the patient support surface removed to showdetails of the foot elevation assembly;

FIG. 11 is an enlarged, partial side elevation view of the hospital bedillustrated in FIG. 1, showing the lower body support panel in aretracted configuration; and

FIG. 12 is an enlarged, partial side elevation view of the hospital bedillustrated in FIG. 1, showing the lower body support panel in anextended configuration.

DETAILED DESCRIPTION

Referring first to FIGS. 1 to 5, there is shown a hospital bed 100, inaccordance with one embodiment. The bed 100 comprises a head end 102, anopposite foot end 104 and spaced-apart left and right sides 105, 107extending between the head end 102 and the foot end 104.

Some of the structural components of the bed 100 will be designatedhereinafter as “right”, “left”, “head” and “foot” from the referencepoint of an individual lying on the individual's back on the supportsurface of the mattress provided on the bed 100 with the individual'shead oriented toward the head end 102 of the bed 100 and theindividual's feet oriented toward the foot end 104 of the bed 100.

The bed 100 includes a base 106, a patient support assembly 108 and anelevation system 110 operatively coupling the patient support assembly108 to the base 106. In the illustrated embodiment, the base 106 isprovided with a displacement assembly 112 which includes casters 114connected to the base 106 by pivots (not shown) hidden from view bycovers 116. This displacement assembly 112 allows the bed 100 to bemoved and maneuvered along a floor. In one embodiment, the base is at adistance of 5 inches from the floor. Alternatively, the base could behigher or lower than 5 inches from the floor.

The elevation system 110 is configured to raise and lower the patientsupport assembly 108 relative to the base 106 between a minimum or fullylowered position and a maximum or fully raised position. In oneembodiment, the elevation system 110 is further configured to allow thepatient support assembly 108 to be set at any intermediate positionbetween the fully lowered and fully raised positions. The elevationsystem 110 may further be configured to tilt the patient supportassembly 108 in various orientations, as will be further explainedbelow.

Still referring to FIG. 1, the bed 100 further includes a patientsupport barrier system 120 generally disposed around the patient supportassembly 108. The barrier system 120 includes a plurality of barrierswhich extend generally vertically around the patient support assembly108. In the illustrated embodiment, the plurality of barriers includes aheadboard 122 located at the head end 102 and a footboard 124 disposedgenerally parallel to the headboard 122 and located at the foot end 104of the bed 100. The plurality of barriers further include spaced-apartleft and right head siderails 126, 128 which are located adjacent theheadboard 122 and spaced-apart left and right foot siderails 130, 132which are respectively located between the left and right head siderails126, 128 and the foot end 104 of the bed 100. Each one of the pluralityof barriers is moveable between an extended or raised position forpreventing the patient lying on the bed 100 from moving laterally out ofthe bed 100, and a retracted or lowered position for allowing thepatient to move or be moved laterally out of the bed 100.

The bed 100 further includes a control interface (not shown) forcontrolling features of the bed 100. The control interface could beintegrated into the footboard 124, into the headboard 122 or into one ormore of the siderails 126, 128, 130, 132. Alternatively, the controlinterface could be provided as a separate unit located near the bed 100or even at a location remote from the bed 100. In one embodiment, thecontrol interface is operatively connected to the elevation system 110to control the height of the patient support assembly 108 above thefloor.

Now referring to FIGS. 2 and 3, the patient support assembly 108includes a frame 200 (best shown in FIG. 4) and a patient supportsurface 250 supported by the frame 200. In the illustrated embodiment,the patient support surface 250 includes an upper body surface orbackrest 252, a lower body surface or lower body support panel 254 andone or more core body surfaces or core support panels 256, 258 locatedbetween the backrest 252 and the lower body support panel 254 forsupporting the seat and/or thighs of the patient. In the illustratedembodiment, each one of the backrest 252, the lower body support panel254 and the core support panels 256, 258 can be angled relative to theother surfaces.

A lying surface such as a mattress or the like, not shown, is typicallyprovided on the patient support surface 250 for receiving the patientthereon. Each one of the backrest 252 and the lower body support panel254 can include a right loop 202 and a left loop 204 which extend abovethe patient support surface 250 to retain the mattress onto the patientsupport surface 250. The right and left loops 202, 204 can also be usedfor hooking on accessories (not shown) used for patient treatment to thebed 100. In the illustrated embodiment, the core support panel 256further includes a left retainer 206 and a right retainer 208 which canalso be used for retaining the mattress onto the patient support surface250 and for hooking on accessories.

Now referring to FIG. 4, the frame 200 includes a pair of longitudinalframe members 402, 404 and a plurality of transversal frame membersextending between the longitudinal frame members 402, 404. In theillustrated embodiment, the plurality of transversal members include afoot transversal member 405 located near the foot end 104 of the bed 100and an intermediate transversal member 406 which is disposed between thefoot transversal member 405 and the head end 102 of the bed 100.Alternatively, the frame 200 could include additional transversalmembers, or a single transversal frame member instead of a plurality oftransversal members.

The bed 100 further includes a backrest pivoting system 450 connectingthe backrest 252 to the frame 200 for pivoting the backrest 252 relativeto the frame 200. In the illustrated embodiment, the bed 100 furtherincludes a lower body pivoting system 452 connecting the lower bodysupport panel 254 and the core support panel 258 adjacent the lower bodysupport panel 254 for pivoting the lower body support panel 254 and thecore support panel 258 relative to the frame 200. The backrest pivotingsystem 450 and the lower body pivoting system 452 will be describedfurther below.

Still referring to FIG. 4, the bed 100 may further comprise a pluralityof hidden hooks for restraining straps which extend below the patientsupport surface 250. In the illustrated embodiment, the plurality ofhidden hooks includes left and right foot hooks 454 a, 454 b and leftand right head hooks 456 a, 456 b.

The bed 100 may further comprise a release or CPR handle assemblyoperatively connected to the backrest pivoting system 450. The CPRhandle assembly may be used in emergency situations by medical personnelto de-couple the backrest 252 from the backrest pivoting system 450 torapidly pivot the backrest 252 to a neutral non-pivoted position, wherethe backrest 252 lies directly on the frame 200. In the illustratedembodiment, the bed 100 comprises left and right CPR handle assemblies460 located respectively near the left and right sides 105, 107 of thebed 100 under the backrest 252. It will be appreciated that providing aCPR handle assembly on both the left and right sides of the bed 100allows the backrest 252 to be rapidly pivoted down regardless of whetherthe operator of the CPR handle assembly is standing on the left side orthe right side 105, 107 of the bed 100. Alternatively, the bed 100 maycomprise a single CPR handle assembly located near one of the left andright sides 105, 107 of the bed 100, or elsewhere on the bed 100 (forexample, at the head end 102 of the bed 100).

Turning to FIG. 4A, the left CPR handle 460 will now be described. Itwill be understood that the same description also applies for the rightCPR handle. In the illustrated embodiment, the CPR handle 460 comprisesa Bowden cable assembly. More specifically, the CPR handle 460 includesa CPR mounting bracket 462 secured to the backrest 252 and a handlemember 464 pivotably connected to the CPR mounting bracket 462 via a pin465. The CPR handle 460 further comprises a cable 466 which has a firstend 468 connected to the handle member 464 and a second end (not shown)connected to the backrest pivoting system 450. Specifically, the handlemember 464 includes a vertical slot 470 which has a straight top portion472 and a bottom circular portion 474 having a diameter greater than thewidth of the top portion 472. The first end of the cable 466 comprisesan enlarged spherical head 476 which has a diameter which is greaterthan the width of the top portion 472, but which is smaller than thediameter of the bottom circular portion 474. This allows the first end468 of the cable 466 to be inserted through the bottom circular portion474 and to be slid in the top portion 472 to be retained therein.

Furthermore, the cable 466 extends within a sheath 478 which includes anend portion 480 and an enlarged diameter portion 482 adjacent the endportion 480. The CPR mounting bracket 462 further comprises a verticalpanel 484 having a hole 486 therein. The hole 486 has a diameter whichis greater than the diameter of the end portion 480 of the sheath 478such that the hole 486 may receive the end portion 480, but which issmaller than the enlarged diameter portion 482. In this configuration,when a user pulls on the handle member 464, the handle member 464 pivotsabout the pin 465 towards the corresponding longitudinal frame members402 and pulls on the cable 466. The enlarged diameter portion 482 of thesheath 478 abuts against the vertical panel 484 and prevents the sheath478 from moving towards the handle member 464, causing the cable 466 tomove relative to the sheath 478 to thereby disengage the backrestpivoting system 450, as will be further explained below. The handlemember 464 may further be biased such that releasing the handle member464 returns the handle member 464 to its initial position. The biasingmay be caused by a resilient member connected to the handle member 464and/or to the pin 465, or using any other biasing means known to theskilled addressee.

Alternatively, the CPR handle assemblies 460 could be configuredaccording to one of various other configurations. For example, the CPRhandle assemblies 460 could comprise a handle which is connected to thebackrest pivoting system 450 via a hydraulic line or anelectrical/optical connection. A button or any other device that couldbe activated by a user may also be provided instead of a handle.

Now turning to FIGS. 5 to 9A, the backrest pivoting system 450 includesleft and right lever arms or members 502, 504 which are spaced from eachother and disposed generally longitudinally relative to the backrest252. As best shown in FIG. 5A, the lever members 502, 504 are disposedbetween the left and right frame members 402, 404 and are generallyparallel thereto.

In the illustrated embodiment, each lever member 502, 504 has agenerally dogleg shape (generally resembling the shape of a hockeystick) and includes a first linear portion 506 which extends along theunderside of the backrest 252 and a second linear portion 508 which isangled downwardly away from the backrest 252 and which extends towardsthe foot end 104 of the bed 100. In one embodiment, the second linearportion 508 is angled relative to the first linear portion 506 by anangle of 117 degrees. Alternatively, the second linear portion 508 couldbe angled relative to the first linear portion 506 by a different angle.

Still in the illustrated embodiment, a bracket member 510 furtherextends between the first and second linear portions 506, 508 of eachlever member 502, 504 to reinforce the lever member 502, 504 and preventbending and/or cracking. A transverse lever member 512 further extendsgenerally horizontally between the second linear portion 508 of the leftlever member 502 and the second linear portion 508 of the right levermember 504. The transverse lever member 512 connects the left and levermembers 502, 504 together and allows them to move as one when a force isapplied on the transverse lever member 512, as will be explained furtherbelow.

The backrest pivoting system 450 further includes a backrest actuator514 for moving the backrest 252 relative to the frame 200. The backrestactuator 514 comprises a first actuator end 516 and a second actuatorend 518. When the backrest actuator 514 is actuated, the second actuatorend 518 moves away from the first actuator end 516. The backrestactuator 514 further comprises a first actuator portion 552 located nearthe first actuator end 516, a second actuator portion 555 located nearthe second actuator end 518 and a transmission 550 operatively couplingthe first actuator portion 552 to the second actuator portion 554 topermit movement of the second actuator portion 554 relative to the firstactuator portion 552. In the illustrated embodiment, the transmission550 is operatively connected to the CPR handle assemblies 460 via thecable 466 such that operation of at least one of the CPR handleassemblies 460 enables the second actuator portion 554 to be selectivelycoupled and uncoupled from the first actuator portion 552, as will befurther explained below.

Still in the illustrated embodiment, the first actuator portion 516 isoperatively connected to the frame 200, and more specifically to theintermediate transversal member 406 of the frame 200, to allow thebackrest actuator 514 to pivot relative to the frame 200, as will beexplained further below. The second actuator end 518 is pivotablyconnected to the transverse lever member 512 via a pivot bracket 520depending from the transverse member 512. A pivot pin 521 engages boththe second actuator end 518 and the pivot bracket 520. The pivot pin 521thereby acts as a pivot which defines a pivot axis P between thebackrest 252 and the backrest actuator 514 which allows the backrest 252to pivot relative to the backrest actuator 514, as will be furtherexplained below.

In one embodiment, the backrest actuator 514 is an electric actuatorincluding a motor and an endless screw, which enables the backrest 252to be pivoted with a relatively high level of precision and in arelatively smooth and continuous movement, regardless of the weight ofthe patient. Alternatively, the backrest actuator 514 could be apneumatic actuator, a hydraulic actuator or any other type of actuatorswhich may be considered suitable for use with the bed 100.

The backrest pivoting system 450 further includes left and right guiderails 522 secured to the frame 200 and left and right guide members 524which are configured to travel along the left and right guide rails 522,respectively. The left and right guide members 524 are configured toguide the backrest 252 during actuation of the backrest actuator 514along a predetermined path defined by the guide rails 522, as will befurther explained below.

Referring specifically to FIG. 5B, each guide rail 522 has a front end526 located towards the head end 102 of the bed 100 and a rear end 528which is located towards the foot end 104 of the bed 100. In theillustrated embodiment, each guide rail 522 has a generally C-shapedcross-section and includes top and bottom faces 530, 532 which extendparallel to each other and a lateral face 534 which extends between thetop and bottom faces 530, 532, perpendicularly thereto. The top andbottom faces 530, 532 are spaced from each other to define therebetweenan open channel 536 which has an open side 538 opposite the lateral face534. The guide rails 522 are oriented such that the lateral faces 534are generally vertical and the open sides 538 of the left and rightguide rails 522 face towards each other. Alternatively, the guide rails522 could have any other configuration suitable to guide the guidemembers 524 along a predetermined path.

In the illustrated embodiment, the guide members 524 includes left andright roller members 540 which are rotatably connected to the secondlinear portion 508 of the left and right lever members 502, 504. Theleft and right roller members 540 are oriented outwardly relative to thebed 100, thereby facing away from each other. The open channels aresized to receive the roller members 540 which rotate about a rotationaxis R which extends in a generally normal direction relative to thelateral face of the guide rail. As best shown in FIG. 5A, the rotationaxes R of the roller members 540 are disposed such that they are bothcoaxial with the pivot axis P defined between the backrest actuator 514and the backrest 252. In this configuration, the backrest actuator 514is able to push and thereby move the backrest 252 without creating anadditional moment on the lever members 502, 504. This reduces the forcethat needs to be applied by the backrest actuator 514 to move thebackrest 252. As will become apparent below, this also reduces thestress in the lever members 502, 504 during pivoting of the backrest 252and thereby prevents damage to the lever members 502, 504.

Alternatively, other types of guide members may be used instead ofroller members. For example, the guide members could instead includesliding members which are pivotably connected to the second linearportion 508 of the left and right lever members 502, 504. Instead ofrolling along the guide rails 522, the sliding members would slide alongthe guide rails when the actuator is extended or retracted, while stillallowing the backrest 252 to pivot relative to the frame 200.

In the illustrated embodiment, the left and right guide rails 522 areangled relative to the frame 200. More specifically, the rear end 528 ofthe guide rails 522 is disposed below the front end 526. The left andright guide rails 522 therefore guide the backrest 252 upwardly and awayfrom the first end of the actuator (i.e. away from the foot end 104 ofthe bed 100) when the backrest actuator 514 is retracted and thebackrest 252 is pivoted away from the frame 200. When the backrestactuator 514 is retracted, the left and right lever members 502, 504 andthe backrest 252 are moved downwardly and towards the foot end 104 ofthe bed 100. In one embodiment, the guide rails 522 may be angled at anangle of 12 degrees relative to the horizontal. Alternatively, the guiderails 522 may be angled at a different angle.

The backrest pivoting system 450 further includes left and rightpivoting links 610 (best shown in FIG. 6B) which cause the backrest 252to pivot as the guide members 524 move along the guide rails 522 whenthe backrest actuator 514 is extended or retracted, as will be furtherexplained below. Each pivoting link 610 has a rear end 612 pivotablyconnected to the backrest 252 and a front end 614 pivotably connected toa respective one of the longitudinal frame members 402, 404. The secondend 614 of the pivoting links 610 is located between the head end 102 ofthe bed 100 and the front end 526 of the guide rails 522. In theillustrated embodiment, the rear end 612 of the pivoting links 610 ispivotably connected to the first linear portion 506 of the left andright lever members 502, 504.

In the illustrated embodiment, there is also provided a damper 560connected in parallel to the backrest actuator 514. The damper 560 isconfigured to provide damping during the pivoting of the backrest 252towards the frame 200 in order to prevent the pivoting of the backrest252 to be too rapid and/or brutal. This is particularly useful duringthe operation of the CPR handle assemblies 460, as will become apparentbelow.

More specifically, the damper 560 comprises a first damper portion 562pivotably connected to the intermediate transversal member 406 and asecond damper portion 564 movable relative to the first damper portion562 and pivotably connected to the transverse lever member 512. Thisconfiguration allows the damper 560 to be angled relative to the frame200 in order to follow movement of the transverse lever member 512 asthe backrest 252 is pivoted. The damper 560 could be a hydraulic damper,a magnetic damper or any other type of dampers known to the skilledaddressee.

Now referring to FIG. 6A, the backrest pivoting system 450 may furthercomprise an orientation sensor 600 (best shown in FIG. 6A) operativelyconnected to the backrest 252 to monitor the orientation of the backrest252. In the illustrated embodiment, the orientation sensor 600 comprisesa rheostat or potentiometer 602 which is embedded into the first linearportion 506 of the right lever member 504. The orientation sensor 600further comprises a first sensor arm 604 pivotably connected to theguide arm 700 and a second sensor arm 606 pivotably connected to thefirst sensor arm 604 and to the potentiometer 602. It will beappreciated that this configuration enables the orientation sensor tomonitor the orientation of the backrest 252 without interfering with themovement of the backrest 252. Alternatively, the orientation sensor maycomprise another type of orientation sensor, such as a gyroscope or anyother orientation sensor known to the skilled addressee.

Still referring to FIG. 6A, the backrest actuator 514 may further bemounted in series with a resilient member. The resilient member may helpto prevent the pivoting of the backrest 252 from stopping too abruptlywhen the CPR handles are used, which could cause discomfort or harm tothe patient and to the medical personnel, as well as damage theelectronic and mechanical components of the bed 100, especially thegears of the backrest actuator 514.

In the illustrated embodiment, the resilient member is a helical spring650 which is housed in a housing 652 secured to the intermediatetransversal member 406 of the frame 200. The helical spring 650 issandwiched between the intermediate transversal member 406 and a piston654 which is pivotally connected to the first actuator portion 552 by apivot pin 656. In the illustrated embodiment, the pivot pin 656 extendsthrough elongated openings in the housing 652, which allows the pivotpin 656 and the piston 654 to move towards the transverse member 406 tocompress the helical spring 650.

In one embodiment, the helical spring 650 is calibrated to be as strongas the maximum load on the backrest actuator 514 when a full load ispresent on the sleep surface. It can also be compressed under the actionof a sudden rotation of the backrest 252. In one embodiment, the springhas a capacity of about 1000 lbs/in and a compression of about ¼ in.

Operation of the backrest pivoting system 450 for pivoting of thebackrest 252 from a non-pivoted position, shown in FIGS. 6 and 6A, to afully pivoted position, shown in FIGS. 9 and 9A, will now be describedin accordance with one embodiment.

In the non-pivoted position shown in FIGS. 6 and 6A, the backrest 252abuts the frame 200. In this position, the backrest 252 is generallyparallel to the core support panel 256 located adjacent to the backrest252. In the illustrated embodiment, the backrest actuator 514 is angleddownwardly relative to the frame 200. More specifically, the backrestactuator 514 is angled downwardly by an angle of 6 degrees.Alternatively, the actuator could be at a different angle relative tothe frame 200 when the backrest 252 is in the non-pivoted position.

Still in the illustrated embodiment, the pivoting links 610 are angledupwardly relative to the frame 200 by an angle of 5 degrees when thebackrest 252 is in the non-pivoted position. Alternatively, the pivotinglinks 610 could be at a different angle relative to the frame 200 whenthe backrest 252 is in the non-pivoted position.

To start the pivoting of the backrest 252, the backrest actuator 514 isactuated. In one embodiment, the backrest actuator 514 is actuated viathe control interface which is operatively connected to the backrestactuator 514. Alternatively, the backrest actuator 514 could be actuatedusing mechanical controls, or using any other means known to the skilledaddressee.

To pivot the backrest 252 upwardly from the non-pivoted position, thebackrest actuator 514 is extended such that the second actuator end 518,which is pivotably connected to the lever members 502, 504 via thetransverse lever member 512, moves away from its first end 516. Thebackrest actuator 514 thereby pushes against the transverse lever member512, which causes the guide members 524, also connected to the levermembers 502, 504, to travel along the guide rails 522.

In FIGS. 7 to 7B, the backrest 252 is shown pivoted at an angle of 20degrees relative to the frame 200. In this position, the roller members524 have been moved along the guide rails 522 from the rear end 528 ofthe guide rails 522 partway towards the front end of the guide rails522. Due to the upward angle of the guide rails 522, this movement alongthe guiderails 522 causes the roller members 524 to be moved upwardlyand forwardly towards the head end 102 of the bed 100. Since the rearend 612 of the pivoting link 610 is pivotably connected to the backrest252 via the lever members 502, 504, the movement of the roller membersfrontwardly along the guide rails 522 causes both the pivoting links 610and the backrest 252 to pivot upwardly relative to the frame 200. As thepivoting links 610 and the backrest 252 pivot upwardly, the angle θbetween the pivoting links 610 and the backrest 252 is therefore reduced(i.e. the angle θ becomes more acute), as best shown in FIG. 7B.

Specifically, each pivoting link 610 pivots such that its rear end 612is raised while its front end 614, which is pivotably connected to theleft frame member 402, remains at the same location. Since FIGS. 7 and7A show the left side 105 of the bed 100, the pivoting links 610 aretherefore shown being pivoted in a clockwise direction relative from thenon-pivoted position shown in FIGS. 6 and 6A. Simultaneously, thebackrest 252 is also pivoted, but in opposite direction to the directionin which the pivoting links 610 are pivoted. In FIGS. 7 and 7A, thebackrest 252 is therefore shown being pivoted in a counter-clockwisedirection. Specifically, the backrest 252 is pivoted relative to theguide rail 200 about the roller member 540, which therefore defines amovable pivot point for the backrest 252.

In the illustrated embodiment, when the backrest 252 is pivoted awayfrom the frame 200, the backrest 252 no longer abuts the frame 200 andis therefore no longer supported by the frame 200. In this position, thepivoting links 610, which extend between the backrest 252 and the frame200, act as truss members to support the backrest 252 and the patientlaying on the bed 100.

It will be appreciated that as the roller members 540, which arepivotably connected to the lever members 502, 504, are moved upwardlyand frontwardly, the transverse lever member 512, which is alsoconnected to the lever members 502, 504, and the second actuator end 518are also moved upwardly and frontwardly. Therefore, the backrestactuator 514 is also pivoted about its pivot pin 656 as it extends andretracts. When the backrest 252 is pivoted upwardly from the non-pivotedposition, the angle between the backrest actuator 514 and the frame 200is therefore reduced (i.e. the angle becomes more acute), as best shownin FIG. 7B.

FIGS. 8 and 8A show the backrest 252 pivoted at a 40-degree anglerelative to the frame 200. In this position, the backrest actuator 514is further extended and the roller members 540 travel further along theguide rails 522, upwardly and towards the head end 102 of the bed 100.This causes both the backrest 252 and the pivoting links 610 to befurther pivoted and the angle between the pivoting links 610 and thebackrest 252 to be further reduced, as best shown in FIG. 8B. The anglebetween the backrest actuator 514 and the frame 200 is also furtherreduced as the roller members 524 travel further along the guide rails522.

FIGS. 9 and 9A show the backrest 252 pivoted at a 60-degree anglerelative to the frame 200. As the backrest actuator 514 is furtherextended, the backrest 252 is further pivoted and further moved alongthe guide rails 522, as described above. It will be understood that thepivoting of the backrest 252 could be stopped at any angle desired andis not limited to the specific angles shown in FIGS. 6 to 9A. It willalso be understood that the backrest 252 could also be pivoteddownwardly towards the non-pivoted position shown in FIGS. 6 and 6A byretracting the backrest actuator 514 instead of extending it.

It will be appreciated that in the bed 100 described herein, extensionand retraction of the backrest actuator 514 therefore simultaneouslycauses both translation and pivoting of the backrest 252 relative to theframe 200. This configuration causes the patient's back to remainrelatively well aligned with the backrest 252 as the backrest 252 ispivoted generally about the patient's hip axis and thereby preventsstrain on the patient's back during this movement. This configurationfurther improves the patient's final position on the bed 100 when theseating position is achieved.

Referring to FIGS. 4A, 6A and 9A, an example of operation of one of theCPR handle assemblies 460 will now be described. In this example, thebackrest 252 is pivoted down using the CPR handle assemblies 460 fromthe position shown in FIG. 9A, in which the backrest 252 is angled at 60degrees relative to the frame 200, to the position shown in FIG. 6A, inwhich the backrest 252 is angled at 20 degrees relative to the frame200. Although operation of a single CPR handle assembly 460 will bedescribed, it will be understood that both of the CPR handle assemblies460 work in the same manner, and that both CPR handle assemblies 460could even be operated simultaneously to achieve the same result.

As explained above, the CPR handle assemblies 460 are operativelyconnected to the transmission 550 of the backrest actuator 514 via thecable 466. The CPR handle assemblies 460 can be moved between a lockedposition in which the first actuator portion 552 is coupled to thesecond actuator portion 554 via the transmission 550 and an unlockedposition in which the transmission 550 is disengaged and the secondactuator portion 554 is decoupled from the first actuator portion 552 toallow free pivoting of the backrest 252 towards the frame 200.

In the illustrated embodiment, the CPR handle assembly 460 is initiallyin the locked position in which no tension is exerted on the cable 466of the CPR handle assemblies 460. Still in the illustrated embodiment,the handle member 464 is biased to maintain the CPR handle assemblies460 in the locked position during normal operation of the bed 100. Itwill be appreciated that when the CPR handle assemblies 460 are in thelocked position, the backrest actuator 514 may be extended or retractedto permit pivoting of the backrest 252 relative to the frame 200 asdescribed above.

To move the CPR handle assemblies 460 from the locked position to theunlocked position, a user pulls on the handle member 464 of the CPRhandle assembly 460, thereby pivoting the handle member 464 about thepin 465. The handle member 464 thereby pulls on the cable 466, whichdisengages the transmission 550 and therefore decouples the firstactuator portion 552 from the second actuator portion 554. When at leastthe CPR handle assembly 460 is in the unlocked position, the backrest252 naturally pivots down towards the frame 200 under the weight of thebackrest 252 itself and/or of the patient lying on the bed 100. It willbe appreciated that the damper 560 damps and therefore slows down thisfree downward pivoting. This can be useful for preventing both thepatient and the user from being startled and/or injured by this freedownward pivoting. However, it will be understood that this freedownward pivoting is still faster than downwardly pivoting the backrest252 by retracting the backrest actuator 514.

When the backrest 252 has reached a desired angle relative to the frame200, the user releases the handle member 464, which is biased backtowards the locked position. The transmission 550 is immediatelyre-engaged and the first actuator portion 552 is recoupled to the secondactuator portion 554. The backrest 252 can then be pivoted againnormally using the backrest actuation system 450, as described above.Alternatively, the handle member 464 may not be biased. In this case,the handle member 464 can be returned to its initial position manuallyby the user.

It will be appreciated that the movement of the CPR handle assembly 460from the unlocked position to the locked position will cause thebackrest 252 to decelerate abruptly or even come to a full stop as thetransmission 550 is re-engaged. This creates an impact on the backrestactuator 514 and on the transmission 550. In the illustrated embodiment,at least part of the energy of this impact is absorbed by the helicalspring 650, which compresses slightly when the handle member 464 isreleased to return the CPR handle assembly 460 to the locked position.This contributes to preventing damage in the transmission, especiallyinner components of the transmission 550 (e.g. gears) and damage to thebackrest actuator 514.

Now referring to FIGS. 10 and 10A, the base 106 and the elevation system110 will now be described. In the illustrated embodiment, the base 106comprises a base frame 1000 having two longitudinal side members 1002,1004, a head member 1006 located towards the head end 102 of the bed 100and a foot member 1008 located opposite the head member 1006 towards thefoot end 104 of the bed 100. In the illustrated embodiment, the headmember 1006 and the foot member 1008 extend between the longitudinalside members 1002, 1004 such that the base frame 1000 defines arectangular shape. The base 106 further comprises a head actuatorbracket 1010 and a foot actuator bracket 1012 which respectively extenddownwardly from the head member 1006 and the foot member 1008.

The elevation system 110 comprises a head elevation assembly 1014located near the head end 102 of the bed 100 and a foot elevationassembly 1016 located near the foot end 104 of the bed 100. In theillustrated embodiment, the head and foot elevation assemblies 1014,1016 are similar to each other. Specifically, the head and footelevation assemblies 1014, 1016 are mirror images of each other.Therefore, only the foot elevation assembly 1016 will be described, withthe same description applying to the head elevation assembly 1014.

The foot elevation assembly 1016 comprises left and right pivoting legmembers 1018, 1020 and an elevation actuator 1022 connecting the baseframe 1000 to the pivoting leg members 1018, 1020. Specifically, theelevation actuator 1022 has a lower end 1024 pivotably connected to thefoot actuator bracket 1012 and an upper end 1026 pivotably connected toa transverse elevation member 1028 extending between the left and rightpivoting leg members 1018, 1020, parallel to the foot member 1008 of thebase frame 1000.

Each pivoting leg member 1018, 1020 comprises an upper end 1030pivotably connected to a respective one of the left and rightlongitudinal frame members 402, 404 and a lower end 1032 pivotably andmovably connected to a respective one of the longitudinal side members1002, 1004 of the base frame 1000. More specifically, each longitudinalside member 1002, 1004 has a longitudinal track 1034 which facesinwardly relative to the bed 100, such that the longitudinal tracks 1034of the two longitudinal side members 1002, 1004 face each other. Aslider member 1036 is pivotably connected to the lower end 1032 of thepivoting leg members 1018, 1020 and slidably engages the correspondinglongitudinal track 1034 to allow the lower end 1032 of the pivoting legmembers 1018, 1020 to selectively slide towards the head end 102 andtowards the foot end 104 of the bed 100.

In the illustrated embodiment, each longitudinal side member 1002, 1004comprises a single longitudinal track adapted to receive the pivotingleg members 1018, 1020 of both the head elevation assembly 1014 and thefoot elevation assembly 1016. Alternatively, each longitudinal sidemember 1002, 1004 could instead comprise two distinct longitudinaltracks: a front longitudinal track to receive the pivoting leg members1018, 1020 of the head elevation assembly 1014 and a rear longitudinaltrack to receive the pivoting leg members 1018, 1020 of the footelevation assembly 1016.

Still in the illustrated embodiment, the foot elevation assembly 1016further comprises left and right pivoting links 1038, 1040 pivotablyconnecting the base frame 1000 to the left and right pivoting legmembers 1018, 1020, respectively. A transverse link member 1042 furtherextends between the left and right pivoting links 1038, 1040, parallelto the transverse elevation member 1042 and the foot member 1008 of thebase frame 1000. Each pivoting link 1038, 1040 has a generally doglegshape (generally resembling the shape of a hockey stick) and has a lowerend 1044 pivotably connected to a link bracket 1046 extending downwardlyfrom the base frame 1000 and an upper end 1048 pivotably connected to arespective pivoting leg member 1018, 1020. As shown in FIG. 10A, thelower end 1024 of the elevation actuator 1022 is located below the lowerend 1044 of the pivoting links 1038, 1040, which are themselves locatedbelow the lower ends 1032 of the pivoting leg members 1018, 1020. Theupper end 1026 of the elevation actuator 1022 is connected to thetransverse elevation member 1028 below the upper end 1030 of thepivoting leg members 1018, 1020, and the upper end 1048 of the pivotinglinks 1038, 1040 is connected to the pivoting leg members 1018, 1020below the upper end 1026 of the elevation actuator 1022.

When the elevation actuator 1022 is extended, its upper end 1026 movesaway from its lower end 1024, thereby pushing against the transverseelevation member 1028 and the pivoting leg members 1018, 1020. Since thepivoting links 1038, 1040 are connected to the pivoting leg members1018, 1020 below the transverse elevation member 1028, the pivotinglinks 1038, 1040 cause the pivoting leg members 1018, 1020 to pivot.More specifically, the upper end 1048 of the pivoting links 1038, 1040defines a pivot point around which the pivoting leg members 1018, 1020pivots as the elevation actuator 1022 extends. As the pivoting legmembers 1018, 1020 pivot, their lower end 1032 move towards theelevation actuator 1022 and their upper end 1030 moves upwardly, therebymoving the frame 200 near the foot end 104 of the bed 100 upwardly andvertically. If only a single one of the head and foot elevationassemblies 1014, 1016 is actuated, the frame 200 is tilted towards theother one of the head and foot elevation assembly 1014, 1016. Forexample, if only the foot elevation assemblies 1016 is raised, as shownin FIGS. 10 to 10B, the frame 200 will tilt towards the head end 102 ofthe bed 100. If the elevation actuators 1022 of both the head and footelevation assemblies 1014, 1016 are extended or retracted at the samespeed and at the same length, then the frame 200 will be raised orlowered relative to the base 106.

In one embodiment, the control interface is operatively connected to theelevation actuator 1022 of the foot elevation assembly 1016 and of thehead elevation assembly 1016 and is configured to allow the user toselectively raise, lower and tilt the frame 200 relative to the base 106by entering a command into the control interface.

Still referring to FIGS. 10 to 10B, the foot pivoting system 452 is usedto simultaneously pivot both the lower body support panel 254 and thecore support panel 258 adjacent the lower body support panel 254. In theillustrated embodiment, the core support panel 258 has a front end 1050hingeably connected to the adjacent core support panel 256 and a rearend 1052 hingeably connected to the lower body support panel 254 via ahinge connection 1054. The lower body support panel 254 has a front end1056 hingeably connected to the core support panel 256 and a rear end1058 which hangs off freely from the foot end 104 of the bed 100.Specifically, the lower body support panel 254 rests on a pair ofrollers 1060 (best shown in FIG. 10B) rotatably connected to the leftand right frame members 402, 404. This allow the lower body supportpanel 254 to be rolled on the rollers 1060 towards the core supportpanel 258 when the core support panel 258 is pivoted upwardly, as willbe explained below. Alternatively, instead of rollers, one or moresliding surfaces may be provided to allow the lower body support panel254 to slide towards the core support panel 258 when the core supportpanel 258 is pivoted upwardly. In yet another embodiment, the rear end1058 of the lower body support panel 254 may instead comprise guidemembers which engage corresponding tracks provided on the left and rightframe members 402, 404.

The foot pivoting system 452 comprises a lower body actuator 1070 (bestshown in FIG. 10) having a rear end 1072 pivotably connected to thelower body transverse member 405 of the frame 200 and a front end 1074pivotably connected to the hinge connection 1054 between the coresupport panel 258 and the lower body support panel 254. In an initial,non-pivoted position, the lower body support panel 254 and the coresupport panel 258 both lay flat on the frame 200. When the lower bodyactuator 1070 is extended from this position, the lower body actuator1070 pushes against the hinge connection 1054, which causes the coresupport panel 258 to pivot about its front end 1050 such that its rearend 1052 is raised above the frame 200. The pivoting of the core supportpanel 258 also causes its rear end 1052 to move forward towards the headend 102 of the bed 100. Since the front end 1056 of the lower bodysupport panel 254 is connected to the rear end 1052 of the core supportpanel 258, the front end 1056 of the lower body support panel 254 isalso raised and moved forward towards the head end 102 of the bed 100.The lower body support panel 254 is therefore pulled forward towards thehead end 102 of the bed 100 while its rear end 1058 still rests on therollers 1060. In this position, the lower body support panel 254 istherefore angled relative to the core support panel 258, as shown inFIGS. 10 and 10A.

It will be appreciated that the foot pivoting system 452 described aboveis only provided as an example, and that the foot pivoting system 452could be configured differently. For example, instead of a single footpivoting system pivoting both the lower body support panel 254 and thecore support panel 258 simultaneously, the bed 100 could comprise afirst pivoting system for pivoting the lower body support panel 254 anda second, distinct pivoting system for pivoting one or more of the coresupport panels. Various alternative configurations known to a skilledaddressee may also be used.

In the illustrated embodiment, the bed 100 is also adapted to beconfigured in a vascular configuration via a command provided on thecontrol interface. The command could be the pressing of a dedicatedbutton on the control interface, for example. This command triggers theappropriate displacement of the support panels and the frame 200 toachieve the vascular configuration, which is shown in FIG. 10. Thisallows the patient to be placed in the vascular position, in which thelegs of the patient are horizontally aligned and are vertically higherthan his heart. To achieve this configuration, the lower body supportpanel 254 and the core support panel 258 are raised with respect to theframe 200 by the foot pivoting system 452, and the backrest 252 isrotated away from the frame 200 by the backrest pivoting system 450. Theframe 200 is tilted by lowering the head elevation assembly 1014, byraising the foot elevation assembly 1016 or by a combination of bothsuch that the head end 102 of the bed 100 is lowered. In one embodiment,the bed 100 is adapted to carry out all of these displacementssimultaneously and at specific speeds such that the lower body supportpanel 254 can be kept parallel to the ground (i.e. horizontal) at alltimes. Alternatively, the displacements described above could be carriedout sequentially (i.e. one after the other).

In one embodiment, the control interface will first sense a current orinitial configuration of the bed 100, and select an appropriatecombination of operations to be performed to achieve the vascularconfiguration depending on the current configuration of the bed 100.Once the appropriate combination of operations is selected, the selectedcombination of operations are performed in sequence or simultaneously,as will be described below. The selected combination is thereforepreprogrammed and no further input is needed from the user or from anysensor until the bed 100 reaches the vascular position. This allow thebed 100 to reach the vascular position rapidly and reliably.

Alternatively, the control interface may not sense an initialconfiguration of the bed 100. In this embodiment, the bed 100 may onlybe placed in the vascular position from one or more predeterminedstarting position.

The operations to be performed for placing the bed 100 in the vascularconfiguration from an initial configuration in which all of the supportpanels are horizontal and the frame 200 is fully raised (i.e. when theelevation actuators 1022 of the head and foot elevation assemblies 1014,1016 are fully extended) will now be described in accordance with oneembodiment.

A command to place the bed in the vascular position is first received.The core support panel 258 is pivoted. Specifically, the lower bodyactuator 1070 is extended, which pushes against the hinge connection1054, as described above. This raises the rear end 1052 of the coresupport panel 258 to be raised above the frame 200, and causes the coresupport panel 258 to be oriented at a core angle above the frame 200.The core support panel 258 is pivoted until it reaches a core angle of30 degrees with respect to the frame 200. As explained above, thepivoting of the core body surface 206 causes pivoting of the lower bodysupport panel 254. In one embodiment, the pivoting of the core supportpanel 258 to a core angle of 30 degrees causes the lower body supportpanel 254 to be oriented at a lower body angle of 13 degrees relative tothe frame 200. The backrest 252 is also pivoted upwardly until itreaches a backrest angle of 13 degrees with the frame 200. The frame 200is further tilted at a tilt angle relative to the horizontal such thatthe head end 102 of the bed 100 is located below the horizontal. In oneembodiment, the tilted angle is selected such that it is within apredetermined range of the lower body angle. In the illustratedembodiment, the frame 200 is tilted by lowering the head elevationassembly 1014 to lower the head end 102 of the bed 100 by an angle of 13degrees below the horizontal, thereby placing the bed 100 in thevascular position. As explained above, all of these displacements can bedone in sequence as presented above or, in one embodiment,simultaneously.

The operations to be performed for placing the bed 100 in the vascularconfiguration from an initial configuration in which all of the supportpanels are horizontal and the frame 200 is fully lowered (i.e. when theelevation actuators 1022 of the head and foot elevation assemblies 1014,1016 are fully retracted) will now be described in accordance with oneembodiment. The core body surface 206 is pivoted upwardly until itreaches an angle of 30 degrees with respect to the frame 200. Thebackrest 252 is also pivoted until it reaches an angle of 13 degree withthe frame 200. Both the head elevation assembly 1014 and the footelevation assembly 1016 are also used to fully raise the frame 200. Thehead elevation assembly 1014 is then lowered to tilt the frame 200 inorder to lower the head end 102 of the bed 100 until it reaches an angleof 13 degrees below the horizontal. As explained above, all of thesedisplacements can be done in sequence as presented above or, in oneembodiment, simultaneously.

From the vascular configuration, the head elevation assembly 1014 andthe foot elevation assembly 1016 may be used to tilt the frame 200 untilit is horizontal. Then, the core support panel 258 and the backrest 252are pivoted back downwardly until they abut the frame 200. In oneembodiment, the control interface is further configured to then fullylower the frame 200 towards the base 106. This lowering of the frame 200could be stopped by a command from the user.

It will be appreciated that other combinations of movements can beselected depending on the initial configuration of the bed 100.

In one embodiment, the lower body support panel 254 and/or the coresupport panel 258 adjacent the lower body support panel 254 are alsoconfigured to pivot downwardly towards a horizontal position when atleast one of the CPR handle assemblies 460 is in the unlocked positionand the backrest 252 is pivoted downwardly. It will be appreciated thatpivoting all support panels downwardly such that the entire patientsupport surface 250 is horizontal and abuts the frame 200 may furtherallow medical personnel to provide suitable emergency care to thepatient lying in the bed 100 in an emergency situation.

In this embodiment, the foot pivoting system 452 comprises a controlunit (not shown) for determining whether the CPR handle assembly 460 isin the unlocked position. Alternatively, the control unit could be partof the control interface, which could be mounted on the bed 100 or beremote from the bed 100 as explained above, and be operatively connectedto the foot pivoting system 452.

In one embodiment, the control unit determines if the CPR handleassembly 460 is in the unlocked position by determining a pivoting speedof the backrest 200. As explained above, when the CPR handle assemblies460 are in the unlocked position, the first and second actuator portions552, 554 of the backrest actuator 514 are uncoupled and the backrest 252is pivoted down under the weight of the backrest 252 and/or of thepatient lying on the bed 100. It will be understood that this pivotingof the backrest 252 using the CPR handle assemblies 460 is used inemergency situations when it may be necessary to place the patient in apredetermined CPR position relatively quickly. The pivoting of thebackrest 252 when the CPR handle assembly 460 is in the unlockedposition is therefore performed at a speed which is substantially higherthan the speed at which the backrest 252 is pivoted by retracting thebackrest actuator 514 for a simple adjustment of the orientation of thebackrest 252. If the determined pivoting speed is above a thresholdspeed value, the control unit therefore determines that the CPR handleassembly 460 is in the unlocked position.

To determine the pivoting speed of the backrest 252, the orientationsensor 600 may be used. More specifically, the control unit may beoperatively connected to the orientation sensor 600 and may beconfigured to receive from the orientation sensor 600 a signalindicative of the orientation of the backrest 252 at a predeterminedfrequency. For example, the foot pivoting system 452 could receive asignal indicative of an orientation angle of the backrest 252 relativeto the frame 200 every 100 millisecond. Alternatively, the foot pivotingsystem 452 could receive a signal from the orientation sensor 600 atanother frequency. In one embodiment, the threshold speed value abovewhich the control unit determines that the CPR handle assembly 460 is inthe unlocked position is 8 degrees per second. Alternatively, thethreshold speed value could be different.

In one embodiment, the control unit is further adapted to detect apivoting direction of the backrest 252. In the example above in whichthe control unit is operatively connected to the orientation sensor 600,the control unit is configured to compare a set of consecutive signalsreceived from the orientation sensor 600. If the signals from the set ofsignals are indicative of decreasing orientation angles of the backrestrelative 252 to the frame 200, then the control unit determines that thebackrest 252 is being pivoted downwardly.

In one embodiment, the control unit is configured to compare every tenconsecutive signals indicative of the orientation of the backrest. In anembodiment in which the signal indicative of the orientation of thebackrest 252 are received by the control unit every 100 milliseconds,the orientation of the backrest 252 would therefore be monitored over aperiod of time of one second.

Alternatively, instead of being operatively connected to the orientationsensor 600, the control unit could be operatively connected to another,distinct orientation sensor coupled to the backrest 252 for determiningan orientation of the backrest 252. In another embodiment, the controlunit could be operatively connected to a speed sensor such as anaccelerometer-based speed sensor or the like.

In another embodiment, the control unit could instead be operativelyconnected to a CPR handle sensor (not shown) to determine whether theCPR handle assembly is in the locked position or the unlocked position.For example, the CPR sensor could be operatively connected to the handlemember 464 of the CPR handle assemblies 460 and could be adapted todetermine whether the handle member 464 is angled by an angle of morethan a threshold angle value, which would be indicative that the handlemember 464 has been pulled and that the CPR handle assembly 460 is inthe unlocked position.

The control unit is further operatively connected to the lower bodyactuator 1070 for actuating the lower body actuator 1070 upon adetermination that the speed of pivoting of the backrest 252 is abovethe threshold speed value and that the backrest 252 is being pivoteddownwardly towards the frame 200. More specifically, the actuator isretracted to pivot the lower body panel 254 and the core body panel 258downwardly towards the frame, as explained above.

In one embodiment, when at least one of the CPR handle assemblies 460 isin the unlocked position and the backrest 252 is being pivoteddownwardly, the lower body support panel 254 and the core support panel258 are pivoted downwardly until they abut the frame 200.

In one embodiment, the actuation of the lower body actuator 1070, andtherefore the pivoting of the lower body support panel 254 and the coresupport panel 258 could be stopped before they abut the frame 200 upon adetection of one or more stop triggers by the control unit. For example,the stop triggers may include a detection that the pivoting of thebackrest 252 has stopped before the backrest 252 has reached an angle of5 degrees or less relative to the frame 200, which may mean that theuser no longer wants to place the support panels 252, 252, 258 in ahorizontal position for emergency care. This may be useful to preventthe lower body support panel 254 and the core support panel 258 fromfully pivoting in a horizontal position if one of the CPR handleassemblies 460 was unlocked inadvertently. In one embodiment, if thebackrest 252 is at an angle of less than 5 degrees relative to the frame200 when the CPR handle assemblies 460 is move from an unlocked positionto a locked position, the pivoting of the lower body support panel 254and the core support panel 258 could still continue until the pivotingof the lower body support panel 254 and the core support panel 258 abutthe frame 200. The stop triggers may further include a detection that acommand has been provided on the control interface, for example if abutton is pressed on the control interface. The stop triggers mayfurther include a loss of power to the control unit, a malfunction ofthe orientation sensor 600 or any other event where the skilledaddressee may consider that stopping the pivoting of the lower bodysupport panel 254 and the core support panel 258 towards a horizontalposition may be desirable.

Alternatively, instead of being retracted, the lower body actuator 1070could be de-coupled similarly to the backrest actuator 514, as describedabove. In this case, the lower body actuator 1070 could also be mountedin series with a resilient member similar to the helical spring 650mounted in series with the backrest actuator 514 in order to reduce theimpact of the re-coupling of the lower body actuator 1070, as describedabove.

Now referring to FIGS. 11 and 12, the bed 100 may also comprise anextendable user support assembly 1100 which allows the lower bodysupport panel 254 to be moved longitudinally away from the core supportpanel 258 adjacent the lower body support panel 254 in order for thelength of the bed 100 to be extended. In the illustrated embodiment, theextendable user support assembly 1100 includes an extension member 1200which has a first end 1202 pivotably connected to the core support panel258 and a second end 1204 which telescopically engages the lower bodysupport panel 254. In one embodiment, the extension member 1200 couldcomprise a pair of spaced-apart rigid rods extending longitudinallyrelative to the bed 100. The lower body support panel 254 includes apair of longitudinal bores sized and shaped for receiving the rigidrods. In this configuration, the rigid rods slide within thelongitudinal bores when the lower body support panel 254 is pulled awayfrom the core support panel 258. It will be appreciated that variousalternative configurations may be possible for the extension member1200.

It will also be appreciated that the extension member 1200 allows thelower body support panel 254 to remain connected to the bed 100 as it ispulled away. Specifically, the extension member 1200 only allowslongitudinal movement of the lower body support panel 254 such that thelower body support panel 254 is still able to pivot when the footpivoting system 452 is actuated as explained above.

When the extendable user support assembly 1100 is extended, as shown inFIG. 12, the extension member 1200 is generally in the same plane as thelower body support panel 254. The extension member 1200 will thereforereceive part of the mattress (not shown) placed on the bed 100. Theextension member 1200 is therefore sized and shaped to support at leastpart of the weight of the mattress provided on the bed 100 and of thepatient's weight.

It will further be understood that as the lower body support panel 254is moved away from the core support panel 258, an opening 1150 is formedbetween the lower body support panel 254 and the core support panel 258.It will be appreciated that this opening 1150 does not cause discomfortto patient since the mattress (not shown), which is typically relativelyrigid, spans over it.

In the illustrated embodiment, the extendable user support assembly 1100can be moved manually using a handle 1160 which extends rearwardly anddownwardly from the rear end 1058 of the lower body support panel 254. Auser pulls on the handle 1160 to move the lower body support panel 254away from the core support panel 258 and pushes the handle 1160 to movethe lower body support panel 254 towards the core support panel 258 andthe head end 102 of the bed 100. Alternatively, the lower body supportpanel 254 may be operatively connected to an extension actuator whichcould be controlled by the control interface to allow the lower bodysupport panel 254 to be moved longitudinally relative to the bed 100using the actuator instead of using the handle 1160.

In the illustrated embodiment, the lower body support panel 254 can bemoved continuously between a retracted position shown in FIG. 11, inwhich the lower body support panel 254 is substantially adjacent thecore support panel 258, and a fully extended position shown in FIG. 12,in which the lower body support panel 254 is prevented from extendingfurther away from the core support panel 258. In one embodiment, thelower body support panel 254 is further adapted to be easily placed intoone or more predetermined intermediate positions between the retractedposition and the fully extended position. For example, the extensionmember 1200 could comprise a notch at a predetermined position along itslength which could be sensed by the user as the user pulls or pushes thelower body support panel 254. Alternatively, the extension member 1200could comprise a visual marker to indicate the intermediate position.

In the illustrated embodiment, when the retracted position, the lowerbody support panel 254 is still slightly spaced from the first end 1202of the extension member 1200. Specifically, the lower body support panel254 is spaced from the first end 1202 of the extension member 1200 by 1inch. In this configuration, the bed 100 may be adapted to receive amattress having a length of 80 inches. Still in the illustratedembodiment, when in the fully extended position, the lower body supportpanel 254 is spaced from the first end 1202 of the extension member 1200by 11 inches. In this configuration, the bed 100 may be adapted toreceive a mattress having a length of 90 inches or, alternatively, amattress having a length of 84 inches and a bolster pad having a lengthof 6 inches. In one embodiment, the extendable user support assembly1100 could also be placed in an intermediate position in which the lowerbody support panel 254 is spaced from the first end 1202 of theextension member 1200 by 5 inches. In this configuration, the bed 100may be adapted to receive a mattress having a length of 84 inches.

It will be appreciated that, in addition to the features describedabove, all hinges and mechanical components of the bed 100 are hiddenunder the patient support surface 250 to provide as littlediscontinuities as possible on the patient support surface 250. Thisfacilitates the cleaning of the bed 100 and its components.

It will also be appreciated that while a hospital bed is used toillustrate the examples described herein, other patient support devices,such as stretchers, adjustable chairs, home-care beds, etc., are alsosuitable for use with the described systems. Moreover, the term“patient” is not intended to be limiting, and can be taken to apply toany user of the support device, such as an individual undergoingshort-term, medium-term or long-term care, a hospital patient, a nursinghome resident, etc.

The embodiments described above are intended to be exemplary only. Thescope of the invention is therefore intended to be limited solely by theappended claims.

I/We claim:
 1. A patient support device comprising: a base; a framesupported relative to the base, the frame configured to support apatient support surface for supporting a patient thereon; and anelevation system for raising or lowering the frame relative to the base,the elevation system including an actuator and a leg assembly coupled tothe frame and the base, the leg assembly including at least one liftingleg, and the actuator mounted in the leg assembly between a first leverand a second lever, the first lever coupled to the lifting leg, and thesecond lever coupled to the base or the frame; wherein the leg assemblycomprises a head end leg assembly, the lift assembly further comprisinga foot end leg assembly, and the foot end leg assembly including alifting leg and an actuator.
 2. The patient support device according toclaim 1, wherein the lifting leg includes an upper pivot connection tothe frame, a lower pivot connection to the base, and a folding pivotaxis between the upper and lower pivot connections, and the first levereccentrically coupled to the lifting leg at the folding pivot axis. 3.The patient support device according to claim 2, wherein the lower pivotconnection comprises a sliding pivot connection, the sliding pivotconnection sliding along a long axis of the base.
 4. The patient supportdevice according to claim 3, wherein the first lever comprises an offsetframe, the offset frame pivotally mounted about the folding pivot axisand pivotally mounted to the sliding pivot connection.
 5. The patientsupport device according to claim 4, wherein the offset frame comprisesa pair of spaced plates, the spaced plates supporting a transverse pin,and the actuator pivotally coupled to the transverse pin.
 6. The patientsupport device according to claim 1, wherein the base includes aplurality of pivoting links.
 7. The patient support device according toclaim 1, wherein the head end leg assembly is independent of the footend leg assembly.
 8. The patient support device according to claim 7,wherein the frame has a foot end and a head end, the lifting leg of oneof foot end leg assembly and the head end leg assembly being pivotallymounted at a fixed pivot connection at or near foot end or the head endof the frame, the lifting leg of the other of the foot end leg assemblyand head end leg assembly being pivotally mounted at a movable fixedpivot connection at or near the foot end or the head end of the frame.9. The patient support device according to claim 7, wherein each of thehead end leg assembly and the foot end leg assembly includes a pair ofthe lifting legs.
 10. The patient support device according to claim 9,wherein each of the actuators is mounted in a respective leg assemblybetween a first lever and a second lever, the first levers comprisingpivotal frames, and each of the pivotal frames mounted between the pairof the lifting legs of the respective leg assembly.
 11. The patientsupport device according to claim 1, wherein the head end leg assemblyand the foot end leg assembly each having an inverted Y-shapedconfiguration when the elevation system moves the frame to a raisedposition.
 12. A patient support device comprising: a base, the basehaving a base frame; a support frame supported relative to the base, thesupport frame configured to support a patient support surface forsupporting a patient thereon; a head end actuator; a foot end actuator;and an elevation system for raising or lowering the frame relative tothe base, the elevation system including a head end leg assembly and afoot end leg assembly, each of the leg assemblies having a Y-shapedconfiguration when the frame is raised and being folded when the frameis lowered, the head end leg assembly and the foot end leg assembly eachhaving a pair of lifting legs, the lifting legs pivotally mounted attheir upper ends to the frame and pivotally mounted at their lower endsto the base, each of the lifting legs having a folding pivot axis, andeach of the head end and foot end actuators having a lower pivotconnection below the base frame and an upper pivot connection above thefolding pivot axis of a respective pair of lifting legs of the liftinglegs.
 13. The patient support device according to claim 13, wherein eachof the actuators is mounted in a respective leg assembly between a firstlever and a second lever, the first levers comprising pivotal frames,and each of the pivotal frames mounted between the pair of the liftinglegs of a respective leg assembly of the head end leg assembly and thefoot end leg assembly.
 14. The patient support device according to claim13, wherein the head end leg assembly and the foot end leg assembly eachhave an inverted Y-shaped configuration when the elevation system movesthe frame to a raised position.
 15. The patient support device accordingto claim 13, wherein the frame has a foot end and a head end, thelifting legs of one of the foot end leg assembly or the head end legassembly being pivotally mounted at fixed pivot connections at or nearthe foot end or the head end of the frame, the lifting legs of the otherof foot end leg assembly and head end leg assembly being pivotallymounted at movable fixed pivot connections at or near the foot end ofthe frame.